Presentation on theme: "Sampling: Your data is only as good as your field technicians."— Presentation transcript:
1 Sampling: Your data is only as good as your field technicians. Jeff Martin, Astrea Taylor,& Nancy Zikmanis
2 Next Phase of the Project Life Cycle PLANNING:SAMPLING:ASSESSMENT:EVALUATION:Plan for data collection using the DQO process Collect data using a SAP and FSOPs Verify that data meets DQOs Make data-based project decisions
3 What’s the Goal? Sampling & analysis objectives: Collect representative samplesObtain accurate and precise analytical dataQuality Assurance Project Plan (QAPP)Laboratory QA/QC programField Standard Operating Procedures (FSOPs) (see handout)VAP does not require QAPPs, but Ohio EPA encourages their use for accurate, representative data
4 Who Collects the Sample? Field staff, usually not the CP or project managerField staff must know how toCollect, handle & manage samplesUnderstand VAP DQOs for sample collection activitiesFollow FSOPsCommunicate with the labCOCs & VAP CertificationContact lab for help when neededComplete Chain of Custody (COC)
5 Field versus Lab ErrorMost error (60 to 80%) associated with environmental sampling and analysis is due to field sampling error rather than lab errorLab QA/QC programs provide strict management and performance controlQA/QC for field sampling activities? We need to rely on FSOPs – typically far less stringent than lab requirements
6 FSOP Purpose?Standard written instructions that document the way sampling activities are performed toMeet project data quality objectivesComply with QAPP (if one exists)Promote quality by properly and consistently implementing accepted methodology (Ohio EPA’s TGM, VAP TDCs)
7 FSOP RecommendationsFollow U.S. EPA and Ohio EPA technical guidance documents (Ohio EPA’s TGM, VAP TDCs)Incorporate flexibility into field investigation as it moves forwardSolicit input from technical experts and field staffU.S. EPA format:Guidance for Preparing Standard Operating Procedures (SOPs), EPA QA/G-6 (EPA/600/B-07/001, April 2007)
8 FSOPs for Sampling In general, three groups of FSOPs: Sampling media (soil, ground water, etc.)Support (decon, field screening, etc.)Transfer of samples from field to lab:QA/QC samples (duplicates, blanks)Sample management (preservation, handling, and shipment)Chain of Custody
9 Maintaining Sample Integrity from the Field to the Laboratory Important Concerns that Need Addressed by SOPs
10 Sampling Practices to Avoid Cross-Contamination While sampling, don’tSmoke or eatWear perfume or cologneHandle fuels, solvents or other chemicalsTouch potentially contaminated surfacesRegularly change sampling gloves, especially before filling sample containersUse disposable or dedicated sampling equipment whenever possible
12 Sampling Practices for Volatile Organic Compounds (VOCs) For soils, use SW-846 Method 5035/5035AFor ground water (Method 8260B), use the low-flow sampling techniqueMinimize sample agitation and aerationSeal sample containers and place on ice ASAP
13 Methods 5035/5035A Low-Level Soil VOCs (< 200 ug/kg) Goal is to collect and preserve soil samples in a manner that minimizes VOC lossStudies indicate significant VOC loss from samples collected using the “bulk soil” or “jar” method (Method 5035A, July 2002, p. 46), problem for low-level VOC samplesSeveral options for collecting/preserving low- level VOC samples
14 Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Sample collection options (coring devices):EnCore™ Sampler (or similar devices):Designed to collect and contain/transport a soil coreSample may be transferred to a 40 ml VOA vial before shipment to labTerra Core Sampler™, Powerstop Handle™ and EasyDraw Syringe™ (or similar devices)Designed to collect and transfer soil cores to VOA vials
17 Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Sample preservation options:Sealed VOA vial on ice (4o+/-2o C)Sodium bisulfate (reacts with carbonate in soil)Methanol (dilution factor, hazardous material/waste)FreezingHolding times:48 hours on ice (4o+/-2o C) in VOA vial from collection to analysis or preservation (field or lab)14 days after preservation to analysis
18 Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) What specific collection/preservation options should I use?Ohio EPA recommends evaluating:Need for low-level soil VOC analyses (DQOs?)Site conditions (carbonate soils? soils with VOCs > 200 ug/kg? very loose or very dense soils?)Difficulty/complexity of effort for field personnel to collect and preserve samples
19 Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Most importantly, discuss the use of these methods with the laboratory and follow their recommended sampling and preservation proceduresNot all laboratories have the same capabilities or preferencesDon’t assume your laboratory will be able to accommodate every 5035/5035A option
20 Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Certified Lab (CL) Rule, OAC (H)(6) states that the CL shall: “Perform analyses in accordance with the laboratory's standard operating procedures and quality assurance program plan approved by Ohio EPA whenever the laboratory produces certified data”
21 Methods 5035/5035A Low-Level Soil VOCs (<= 200 ug/kg) Phase II Rule, OAC (D)(3)(a) states that field QA/QC procedures must include a: “Review of the laboratory’s quality assurance program plan and standard operating procedures for consistency with field quality assurance and quality control procedures”
22 Ground Water Sampling Issues (Reminder) Sample representativeness?Depends on adequacy of well development and sampling techniques:Adequate well development?Sufficient stabilization time between development and sampling?Proper purging and sampling techniques, e.g., adequate purging prior to sampling?Refer to Ohio EPA’s TGM Chapters 6 and 10
23 Ground Water VOC Samples Filling 40 ml VOC vials with ground or surface water (zero headspace):Fill slowly (100 mL/min) to minimize agitation and aerationForm a meniscus and then slowly screw on cap to seal the sampleCheck for bubbles by inverting vial and gently tapping itCollect at least two vials for each sample
24 Ground Water VOC Samples Air bubbles in 40 mL vials may be caused byInsufficient meniscus when sealing the vialDegassing after sample collection or during sample shipmentReaction between the sample and preservative (HCl)Air bubbles do not necessarily invalidate the sampleU.S. EPA studies indicate that bubbles smaller than ¼- inch (pea-sized) do not adversely affect the sample
25 Ground Water VOC Samples If air bubbles are present in a 40 mL VOC vial immediately after sample collection…Discard vial and collect another sample using a new vialDon’t re-open and “top off” the vial, this may compromise the sample throughAdditional exposure to ambient airLoss of preservative
26 Ground Water VOC Samples If air bubbles are noticed in a 40 mL VOC vial during sample cooler packing…Recollect the sample if the bubble is ¼-inch (pea- sized) or greater in diameterOtherwise, submit the sample to the laboratoryIf sample reacts with preservative, may need to collect an unpreserved sample
27 Quality Assurance/Quality Control (QA/QC) MinimizeSources of sampling and analytical errorPotential cross-contaminationMaximizeSample representativenessAnalytical data accuracy and precision
28 VAP Phase II QA/QC Procedures OAC 3745-300-07(D)(3) Review lab QA/QC procedures – are field QA/QC procedures consistent?QA/QC procedures, not limited to the following:Equipment decontaminationQA/QC samplesField instrument calibrationDocumentation and record maintenanceSampling handling, preservation and holding timesChain of custody
29 QA/QC Samples Sample Type: When to Submit: Trip Blanks Equipment (Rinsate) BlanksField BlanksFilter BanksDuplicate SamplesOne (1) per sample cooler, VOCs onlyIf non-dedicated, non-disposable sampling equipment is usedNeeded based on field conditionsRecommended for field filteringOne (1) per 20 samples, typically not collected for soil (due to soil matrix heterogeneity)
30 QA/QC Samples Matrix Spike / Matrix Spike Duplicate (MS/MSD): Fill all containers that the lab provides (if four 1-L jars are required, don’t return only two)Don’t use the most contaminated sample for the MS/MSD (may adversely affect the lab QA/QC results)Follow the lab’s advice for the MS/MSD and other QA/QC samples (they know what they need)
31 Sample Management: Preservation Prevents physical and chemical changes to sample during transportation and storageMaintains representative constituent concentrations byReducing volatilityPreventing hydrolysisRetarding biodegradation
32 Sample Management: Preservation Methods generally usedpH control (add strong acid or base)Chemical addition (stabilization other than pH control, e.g., Na2S2O3)Temperature control (cool to 4o +/- 2o C)Protection from light (amber glass sample containers)Field staff need to understand the purpose of preservation and methods
33 Sample Management: Preservation Preservatives may react with sampleVOC ground water sample containing carbonate minerals reacts with HCl preservativeSolution: collect an unpreserved sampleSample holding time will be significantly shorterField staff need to inform lab (must understand the relationship between preservation and holding time requirements)
34 Sample Management: Preservation Use pre-preserved sample containers or add preservatives in the field?Most labs provide pre-preserved sample containersMay want to carry additional preservative in the fieldAdding preservatives to containers in the field presents additional health & safety concerns (field staff need to be aware of potential hazards)
36 Sample Management: Preservation Temperature control – recommend using ice rather than ice substitute (“blue ice”)Generally less effective at maintaining the required cooler temperaturePotential source of chemical cross-contaminationPropylene glycolStyreneAmmonium chloride
37 Sample Management: Preservation Use sealable plastic bags to contain iceAvoid immersing sample containers in water (damaged labels, cross-contamination)Avoid leaking coolers; also use plastic cooler liner (or commercial shipper may not deliver)About 1/3 of cooler should be iceAvoid the use of “blue ice”Ice is cheaper than resampling.
38 Sample Management: Preservation Verification of proper temperature preservation:Presence of ice in coolerMeasurement of internal cooler temperatureTemperature blankRecommendedOne per coolerDon’t encase in ice or freeze
39 Sample Management: Containers & Labeling Specifications per analytical methods (SW-846)Generally provided by labStockpiled containers from previous projects? Not recommended:Loss of preservativesCross-contamination issuesInconsistency with current project lab
40 Sample Management: Containers & Labeling Labels may be completed in field or (mostly) pre- populated by laboratoryLabels should be waterproof and securely affixed to each sample containerPermanent marker or ink (legible if wet)Protect completed labels with clear tape (except for pre-weighed containers)Recommend completing and affixing label after sample container is filled
41 Sample Management: Containers & Labeling Label informationSample identification (per FSOP?)Date and time collected (AM/PM or military time)Analytical methods/constituents requestedField staff need to be familiar with methods and their respective constituentsPreservativesName or initials of sampler
42 Sample Management: Shipping Use coolers to ship samples (temperature preservation requirements)Seal ice in plastic bags, use cooler linerShip containers uprightUse packing to protect glass containers, e.g., bubble wrap, styrofoam, etc.Deliver to laboratory via commercial carrier (UPS, FedEx, etc.) or courier
44 Sample Management: Shipping Include the chain of custody (COC) form in the cooler (in a sealed plastic bag)Use an individual COC for each cooler rather than a single COC for multiple coolersWhat if the cooler with the COC doesn’t arrive at the lab with the other coolers?If any cooler in a multiple cooler shipment under a single COC exceeds temp requirements, samples in all coolers will be flagged for temp
45 Sample Management: Shipping Regulations (DOT), requirements (shipper)Hazardous materials (LNAPL, methanol)?Cooler weight?Type of tape used, cooler labeling?Securely seal coolerAffix custody seal with protective tape
46 Sample Management: Shipping Shipping method depends on holding timesHexavalent chromium?SVOCs by 8270?Unpreserved VOCs by 8260?Recommend sampling constituents with short holding times lastImportant for field staff to understand analytical methods and holding time requirements
47 Sample Management: Shipping Using a commercial shipper?Should know drop off locations and business hours before samplingCall locations to verify, just don’t rely on internetSaturday delivery?Complete appropriate shipping formsCall the lab to confirm deliver location
48 Chain of Custody (COC)COC form: critical communication between field samplers and the laboratoryTechnical and legal record of samples collected, analyses requested and sample custodyField staff must understand how to properly complete COC forms – what does this mean?
49 Chain of Custody (COC)Field staff should understand the following to properly complete COC forms:Project and contact informationSample ID nomenclatureAnalytical methods:Method numbers/referencesContainer types and volume requirementsPreservative requirementsHolding times
50 Chain of Custody (COC)Field staff should understand the following to properly complete COC forms (continued):QA/QC samples (trip blanks, duplicates, etc.)Type and quantity neededHow to designate/record on formInformation to include as comments or notesDetection limit or certification requirements (VAP)Highly contaminated samples or other matrix issuesSpecial sampling handling/processing requirements
53 Chain of Custody (COC) Review for accuracy and completeness Don’t forget to sign COC with date & timeRetain a copy before shipping samplesCommercial carriers (e.g., UPS) will not sign a COC – Ohio EPA recommends retaining a copy of the shipping form for documentation of sample custody during transportation
54 Laboratory Interaction Field staff need a lab contact to address:Questions about method requirements (e.g., preservation, holding times)Questions about VAP certificationNeed for additional sample containers or suppliesSample matrix concerns (highly contaminated samples, unpreserved samples)Weekend delivery (sample receiving)
55 Laboratory Interaction In most cases, the lab is a contractor retained by the consultantBoth the consultant and lab have common objectives:Collect representative samplesObtain accurate and precise analytical dataMutual understanding, cooperation, and tact will greatly facilitate these objectives
57 Vapor Intrusion (VI) Sampling & Analysis Background:Has been recognized as a potential pathway of contamination for almost 20 years.In the late 1980s, the first vapor intrusion studies were carried out to evaluate potential health effects from chronic exposure to volatile organic compounds.For labs, this has created an upward trend in the number of ambient air, indoor air, soil gas and sub-slab samples submitted each year for volatile organic compound (VOC) analyses.
58 Vapor Intrusion (VI) Sampling & Analysis The primary compounds of concern are often chlorinated VOCs. Trichloroethene (TCE) and tetrachloroethene (PCE), in particular, are common targets of the investigations due to the health risks associated with these compounds and their breakdown products.
59 Sample Collection… Silicon-lined canister (Silonite®) Tedlar Bag Varying sizes for GRAB v. TIMED SamplesGRAB Sample only
63 Canister Cleanliness – HOW CLEAN IS CLEAN? Should you request a “Certificate of Cleanliness” for each canister?
64 Laboratory Analysis: USEPA Method TO-15 The most frequently requested method for the analysis of VOCs for the range of air samples associated with vapor intrusion investigations.A wide range of compounds (40 to 60) may be analyzed by EPA TO-15 including alkanes, alkenes, aromatics, halogenated VOCs, ketones, esters and some alcohols. (Some aldehydes and sulfides may also be evaluated using this method.)Some variation among commercial environmental laboratories in the compound lists (must be specific when communicating with lab).Results reported in μg/m3, ppbV, or both. YOU SHOULD REQUEST BOTH!!!Compound lists can usually be tailored to meet project-specific objectives.
65 Summary PointsCommunicate: >Talk to the lab about equipment/canisters Grab v. Time Integrated.>Discuss reporting units – ASK FOR BOTH ug/m3 and ppbv.>Discuss most appropriate method – TO or TO-15 SIM.>“Certify” each canister? Or accept “batch” decon?>Verify that lab has CURRENT VAP CERTIFICATION for the analysis.
66 Summary Points Communicate: >Talk to the lab about equipment/canisters Grab v. Time Integrated.>Discuss reporting units – ug/m3 and ppbvASK FOR BOTH!>Discuss most appropriate method – TO-15 or TO-15 SIM.>“Certify” each canister? Or accept “batch” decon?>Verify that lab has CURRENT VAP CERTIFICATION for the analysis.
67 Any additional questions or comments? Thanks for your time and attention!